I want to see development outside of stats, and more related to the character's personality developing. Granted, you can't throw out stats without ruining the enjoyment a lot of players have with stat crunching, but I'd love to see a system that blends a PC's personality and stat development together in one package, and then dumps them in a world where both are important. For me, the key moment of a role-playing game (at least pen and paper) is the interaction you get from other player characters and NPCs and any changes that occur in your character as a result. I would like to see more games that take advantage of (and track) personality types and traits to help a player define a character and give them more tangible benefits (some of this was done in the SPECIAL system in Fallout, and it was a refreshing change, though there was no tracking throughout the game). Before I left Black Isle, Josh Sawyer had worked up some nice personality-tracking mechanics for the Jefferson project, which were a breath of fresh air.